Chemical analysis of the quality of the In-Ceram-system presumes a complete understanding and knowledge about its microstructure and its chemical and macroscopic composition. As far as science is concerned, the knowledge about ionic exchange in the borderline of compound materials (such as glass - infiltered aluminium oxide and ceramics) is mandatory. This knowledge could be the base for further results in the research about the persistency, the process of erosion and the wearing-out, as well as the mechanisms of fracture of the In-Ceram-system in the oral cavity. Schlagwörter: In-Ceram, ceramic